runtime: better stack traces in race reports

When a race happens inside of runtime (chan, slice, etc),
currently reports contain only user file:line.
If the line contains a complex expression,
it's difficult to figure out where the race exactly.
This change adds one more top frame with exact
runtime function (e.g. runtime.chansend, runtime.mapaccess).

R=golang-dev
CC=golang-dev
https://golang.org/cl/6851125

6 files changed, 53 insertions, 35 deletions

diff --git a/src/pkg/runtime/chan.c b/src/pkg/runtime/chan.c
index 0aa0b43c56..9b915cef01 100644
--- a/src/pkg/runtime/chan.c
+++ b/src/pkg/runtime/chan.c
@@ -188,7 +188,7 @@ runtime·chansend(ChanType *t, Hchan *c, byte *ep, bool *pres, void *pc)
 	runtime·lock(c);
 	// TODO(dvyukov): add similar instrumentation to select.
 	if(raceenabled)
-		runtime·racereadpc(c, pc);
+		runtime·racereadpc(c, pc, runtime·chansend);
 	if(c->closed)
 		goto closed;
 
@@ -1193,7 +1193,7 @@ runtime·closechan(Hchan *c)
 	}
 
 	if(raceenabled) {
-		runtime·racewritepc(c, runtime·getcallerpc(&c));
+		runtime·racewritepc(c, runtime·getcallerpc(&c), runtime·closechan);
 		runtime·racerelease(c);
 	}
 
diff --git a/src/pkg/runtime/hashmap.c b/src/pkg/runtime/hashmap.c
index 4869669b6e..60c592184e 100644
--- a/src/pkg/runtime/hashmap.c
+++ b/src/pkg/runtime/hashmap.c
@@ -842,7 +842,7 @@ runtime·mapaccess1(MapType *t, Hmap *h, ...)
 	bool pres;
 
 	if(raceenabled && h != nil)
-		runtime·racereadpc(h, runtime·getcallerpc(&t));
+		runtime·racereadpc(h, runtime·getcallerpc(&t), runtime·mapaccess1);
 
 	ak = (byte*)(&h + 1);
 	av = ak + ROUND(t->key->size, Structrnd);
@@ -870,7 +870,7 @@ runtime·mapaccess2(MapType *t, Hmap *h, ...)
 	byte *ak, *av, *ap;
 
 	if(raceenabled && h != nil)
-		runtime·racereadpc(h, runtime·getcallerpc(&t));
+		runtime·racereadpc(h, runtime·getcallerpc(&t), runtime·mapaccess2);
 
 	ak = (byte*)(&h + 1);
 	av = ak + ROUND(t->key->size, Structrnd);
@@ -901,7 +901,7 @@ reflect·mapaccess(MapType *t, Hmap *h, uintptr key, uintptr val, bool pres)
 	byte *ak, *av;
 
 	if(raceenabled && h != nil)
-		runtime·racereadpc(h, runtime·getcallerpc(&t));
+		runtime·racereadpc(h, runtime·getcallerpc(&t), reflect·mapaccess);
 
 	if(t->key->size <= sizeof(key))
 		ak = (byte*)&key;
@@ -974,7 +974,7 @@ runtime·mapassign1(MapType *t, Hmap *h, ...)
 		runtime·panicstring("assignment to entry in nil map");
 
 	if(raceenabled)
-		runtime·racewritepc(h, runtime·getcallerpc(&t));
+		runtime·racewritepc(h, runtime·getcallerpc(&t), runtime·mapassign1);
 	ak = (byte*)(&h + 1);
 	av = ak + ROUND(t->key->size, t->elem->align);
 
@@ -992,7 +992,7 @@ runtime·mapdelete(MapType *t, Hmap *h, ...)
 		runtime·panicstring("deletion of entry in nil map");
 
 	if(raceenabled)
-		runtime·racewritepc(h, runtime·getcallerpc(&t));
+		runtime·racewritepc(h, runtime·getcallerpc(&t), runtime·mapdelete);
 	ak = (byte*)(&h + 1);
 	runtime·mapassign(t, h, ak, nil);
 
@@ -1017,7 +1017,7 @@ reflect·mapassign(MapType *t, Hmap *h, uintptr key, uintptr val, bool pres)
 	if(h == nil)
 		runtime·panicstring("assignment to entry in nil map");
 	if(raceenabled)
-		runtime·racewritepc(h, runtime·getcallerpc(&t));
+		runtime·racewritepc(h, runtime·getcallerpc(&t), reflect·mapassign);
 	if(t->key->size <= sizeof(key))
 		ak = (byte*)&key;
 	else
@@ -1040,7 +1040,7 @@ runtime·mapiterinit(MapType *t, Hmap *h, struct hash_iter *it)
 		return;
 	}
 	if(raceenabled)
-		runtime·racereadpc(h, runtime·getcallerpc(&t));
+		runtime·racereadpc(h, runtime·getcallerpc(&t), runtime·mapiterinit);
 	hash_iter_init(t, h, it);
 	it->data = hash_next(it);
 	if(debug) {
@@ -1085,7 +1085,7 @@ void
 runtime·mapiternext(struct hash_iter *it)
 {
 	if(raceenabled)
-		runtime·racereadpc(it->h, runtime·getcallerpc(&it));
+		runtime·racereadpc(it->h, runtime·getcallerpc(&it), runtime·mapiternext);
 	if(runtime·gcwaiting)
 		runtime·gosched();
 
@@ -1190,7 +1190,7 @@ reflect·maplen(Hmap *h, intgo len)
 	else {
 		len = h->count;
 		if(raceenabled)
-			runtime·racereadpc(h, runtime·getcallerpc(&h));
+			runtime·racereadpc(h, runtime·getcallerpc(&h), reflect·maplen);
 	}
 	FLUSH(&len);
 }
diff --git a/src/pkg/runtime/race.c b/src/pkg/runtime/race.c
index aae43852a3..3cff49d7f9 100644
--- a/src/pkg/runtime/race.c
+++ b/src/pkg/runtime/race.c
@@ -152,24 +152,40 @@ runtime·racegoend(int32 goid)
 	m->racecall = false;
 }
 
-void
-runtime·racewritepc(void *addr, void *pc)
+static void
+memoryaccess(void *addr, uintptr callpc, uintptr pc, bool write)
 {
+	int64 goid;
+
 	if(!onstack((uintptr)addr)) {
 		m->racecall = true;
-		runtime∕race·Write(g->goid-1, addr, pc);
+		goid = g->goid-1;
+		if(callpc) {
+			if(callpc == (uintptr)runtime·lessstack ||
+				(callpc >= (uintptr)runtime·mheap.arena_start && callpc < (uintptr)runtime·mheap.arena_used))
+				runtime·callers(3, &callpc, 1);
+			runtime∕race·FuncEnter(goid, (void*)callpc);
+		}
+		if(write)
+			runtime∕race·Write(goid, addr, (void*)pc);
+		else
+			runtime∕race·Read(goid, addr, (void*)pc);
+		if(callpc)
+			runtime∕race·FuncExit(goid);
 		m->racecall = false;
 	}
 }
 
 void
-runtime·racereadpc(void *addr, void *pc)
+runtime·racewritepc(void *addr, void *callpc, void *pc)
 {
-	if(!onstack((uintptr)addr)) {
-		m->racecall = true;
-		runtime∕race·Read(g->goid-1, addr, pc);
-		m->racecall = false;
-	}
+	memoryaccess(addr, (uintptr)callpc, (uintptr)pc, true);
+}
+
+void
+runtime·racereadpc(void *addr, void *callpc, void *pc)
+{
+	memoryaccess(addr, (uintptr)callpc, (uintptr)pc, false);
 }
 
 void
@@ -266,7 +282,7 @@ void runtime·RaceSemrelease(uint32 *s)
 void
 runtime·RaceRead(void *addr)
 {
-	runtime·racereadpc(addr, runtime·getcallerpc(&addr));
+	memoryaccess(addr, 0, (uintptr)runtime·getcallerpc(&addr), false);
 }
 
 // func RaceWrite(addr unsafe.Pointer)
@@ -274,7 +290,7 @@ runtime·RaceRead(void *addr)
 void
 runtime·RaceWrite(void *addr)
 {
-	runtime·racewritepc(addr, runtime·getcallerpc(&addr));
+	memoryaccess(addr, 0, (uintptr)runtime·getcallerpc(&addr), true);
 }
 
 // func RaceDisable()
diff --git a/src/pkg/runtime/race.h b/src/pkg/runtime/race.h
index 9ebb9d3738..6ae9629411 100644
--- a/src/pkg/runtime/race.h
+++ b/src/pkg/runtime/race.h
@@ -20,8 +20,8 @@ void	runtime·racemalloc(void *p, uintptr sz, void *pc);
 void	runtime·racefree(void *p);
 void	runtime·racegostart(int32 goid, void *pc);
 void	runtime·racegoend(int32 goid);
-void	runtime·racewritepc(void *addr, void *pc);
-void	runtime·racereadpc(void *addr, void *pc);
+void	runtime·racewritepc(void *addr, void *callpc, void *pc);
+void	runtime·racereadpc(void *addr, void *callpc, void *pc);
 void	runtime·racefingo(void);
 void	runtime·raceacquire(void *addr);
 void	runtime·raceacquireg(G *gp, void *addr);
diff --git a/src/pkg/runtime/race0.c b/src/pkg/runtime/race0.c
index 82ebba8229..0553e17093 100644
--- a/src/pkg/runtime/race0.c
+++ b/src/pkg/runtime/race0.c
@@ -26,16 +26,18 @@ runtime·racemapshadow(void *addr, uintptr size)
 }
 
 void
-runtime·racewritepc(void *addr, void *pc)
+runtime·racewritepc(void *addr, void *callpc, void *pc)
 {
 	USED(addr);
+	USED(callpc);
 	USED(pc);
 }
 
 void
-runtime·racereadpc(void *addr, void *pc)
+runtime·racereadpc(void *addr, void *callpc, void *pc)
 {
 	USED(addr);
+	USED(callpc);
 	USED(pc);
 }
 
diff --git a/src/pkg/runtime/slice.c b/src/pkg/runtime/slice.c
index 2f62c4c02d..e2c76eb8e7 100644
--- a/src/pkg/runtime/slice.c
+++ b/src/pkg/runtime/slice.c
@@ -83,11 +83,11 @@ runtime·appendslice(SliceType *t, Slice x, Slice y, Slice ret)
 	if(raceenabled) {
 		pc = runtime·getcallerpc(&t);
 		for(i=0; i<x.len; i++)
-			runtime·racereadpc(x.array + i*t->elem->size, pc);
+			runtime·racereadpc(x.array + i*t->elem->size, pc, runtime·appendslice);
 		for(i=x.len; i<x.cap; i++)
-			runtime·racewritepc(x.array + i*t->elem->size, pc);
+			runtime·racewritepc(x.array + i*t->elem->size, pc, runtime·appendslice);
 		for(i=0; i<y.len; i++)
-			runtime·racereadpc(y.array + i*t->elem->size, pc);
+			runtime·racereadpc(y.array + i*t->elem->size, pc, runtime·appendslice);
 	}
 
 	if(m > x.cap)
@@ -118,9 +118,9 @@ runtime·appendstr(SliceType *t, Slice x, String y, Slice ret)
 	if(raceenabled) {
 		pc = runtime·getcallerpc(&t);
 		for(i=0; i<x.len; i++)
-			runtime·racereadpc(x.array + i*t->elem->size, pc);
+			runtime·racereadpc(x.array + i*t->elem->size, pc, runtime·appendstr);
 		for(i=x.len; i<x.cap; i++)
-			runtime·racewritepc(x.array + i*t->elem->size, pc);
+			runtime·racewritepc(x.array + i*t->elem->size, pc, runtime·appendstr);
 	}
 
 	if(m > x.cap)
@@ -153,7 +153,7 @@ runtime·growslice(SliceType *t, Slice old, int64 n, Slice ret)
 	if(raceenabled) {
 		pc = runtime·getcallerpc(&t);
 		for(i=0; i<old.len; i++)
-			runtime·racewritepc(old.array + i*t->elem->size, pc);
+			runtime·racewritepc(old.array + i*t->elem->size, pc, runtime·growslice);
 	}
 
 	growslice1(t, old, cap, &ret);
@@ -213,8 +213,8 @@ runtime·copy(Slice to, Slice fm, uintptr width, intgo ret)
 	if(raceenabled) {
 		pc = runtime·getcallerpc(&to);
 		for(i=0; i<ret; i++) {
-			runtime·racewritepc(to.array + i*width, pc);
-			runtime·racereadpc(fm.array + i*width, pc);
+			runtime·racewritepc(to.array + i*width, pc, runtime·copy);
+			runtime·racereadpc(fm.array + i*width, pc, runtime·copy);
 		}
 	}
 
@@ -259,7 +259,7 @@ runtime·slicestringcopy(Slice to, String fm, intgo ret)
 	if(raceenabled) {
 		pc = runtime·getcallerpc(&to);
 		for(i=0; i<ret; i++) {
-			runtime·racewritepc(to.array + i, pc);
+			runtime·racewritepc(to.array + i, pc, runtime·slicestringcopy);
 		}
 	}